Field
The present invention relates to an LED lighting apparatus, and more particularly, to an LED lighting apparatus, such as a street light, a security light or a factory light, which requires good heat dissipation characteristic.
Discussion of the Background
A halogen lamp, a mercury-vapor lamp, a metal halide lamp, a sodium-vapor lamp or the like have been used for the light source of a high output lighting apparatus such as a street light, a security light or a factory light. Such lamps have low economic feasibility because high power consumption is caused by the low efficiency. In addition, there is a problem that the lifetime of the lamp and electronic ballast is shortened. Furthermore, since most of lamps include environmentally harmful substances such as mercury, the use thereof has been restricted.
Recently, Light Emitting Diodes (LEDs) have attracted attention as light sources to resolve the problems of existing lamps for a lighting apparatus. The LEDs have advantages of long life time and low power consumption, and are environment friendly by not using environmentally harmful substances, for example, mercury.
In order to apply the LEDs as a light source for a lighting apparatus which requires high light output, such as a street light, a security light or a factory light, an LED module in which a plurality of LEDs are integrated with high density is required. The LED module having high-density integrated LEDs generates high temperature heat upon operation of the LEDs. The high temperature heat reduces the light-emitting efficiency of the LEDs and shortens the lifetime thereof. In particular, the high output LED lighting apparatus such as a street light, a security light or a factory light requires high voltage power for the operation of the LEDs. As a result, the high temperature heat is generated, and thus, thermal stress on the LEDs leads to the degradation of characteristics and frequent breakdown, which have been pointed out as serious disadvantages.
In order to the above-described problems, an existing LED lighting apparatus includes a heat dissipation structure having good heat conductivity, such as a heat sink or a heat dissipation plate, in a part on which the LED module is mounted. However, due to limitations in the characteristics of a metal material of which the heat dissipation structure is formed, the thickness of the heat radiation structure may become larger excessively in order to satisfy required heat dissipation performance.
In addition, in an LED lighting apparatus for emitting light downwardly, such as a street light, a security light or a factory light, the ratio of direct light which is emitted from the LED and is straightly directed downwardly without passing through a reflective surface is high. The LED is characterized in that straightness is high, that is, an orientation angle is narrow, and, therefore, in the case of the LED lighting apparatus used to illuminate a predetermined area, it may be advantageous to increase the amount of light passing through a reflective surface. However, mounting a separate reflection member does not allow the lighting apparatus to be compact or slim and is economically disadvantageous.
Since the existing LED lighting apparatus is exposed to a harsh external environment including rain, snow, dust, etc., the LED module needs to be disassembled for the replacement, cleaning or repair of the LED module in the case of breakdown, irregular operation or heavy pollution. However, the existing LED lighting apparatus has a structure in which the LED module is directly connected to a heat dissipation structure having large volume, thus making the disassembly of the LED module difficult.